High strength fibers and filaments are widely used in ballistic resistant articles, such as bullet proof vests, curtains, mats, raincoats and umbrellas. Exemplary high strength fibers include aramid fibers, high molecular weight polyethylene fibers, nylon fibers, glass fibers, and the like. Various ballistic resistant articles which include high strength fibers made from materials such as high molecular weight polyethylene are described, for example, in U.S. Pat. Nos. 4,820,568; 4,748,064; 4,737,402; 4,737,401; 4,681,792; 4,650,710; 4,623,574; 4,613,535; 4,584,347; 4,563,392; 4,543,286; 4,501,856; 4,457,985; and 4,403,012.
For many ballistic resistant articles, such as vests, linings, and the like, flexibility is a desired characteristic for comfort and mobility of the wearer. In these and other applications, typically the ballistic resistant article includes a plurality of woven or knit fabrics formed of high strength fibers and/or filaments. For example, U.S. Pat. No. 4,737,401 describes various woven fabrics made from high molecular weight extended chain polyethylene and polypropylene yarns, extended chain polyvinyl alcohol yarns, and extended chain polyacrylonitrile yarns. U.S. Pat. No. 4,681,792 describes articles which include first and second portions, the first portion comprising a plurality of layers of a first woven fabric and the second portion comprising a plurality of layers of a second woven fabric. The fabrics of each of the first and second portions are selected to provide differing resistances to displacement of the fibers therein.
U.S. Pat. No. 5,135,804 describes the application of heat and pressure to a network of high strength polyethylene fibers, including woven high strength polyethylene fabrics, to provide an article having consolidation among the fibers to one of four levels. The fiber network is treated at temperatures ranging from 100.degree. C. to 160.degree. C. (212.degree. F. to 320.degree. F.) and pressures ranging from 0.5 to 1 MPa (in an autoclave) up to 1 to 200 MPa (in a molding press). The patent indicates that temperatures and pressures at the high end of these ranges, which deform the fibers and form film-like structures, are required to achieve ballistic-resistant articles.
These and other structures of high strength fibers can provide good ballistic performance when incorporated into a ballistic resistant article, such as a vest. However, to provide the desired degree of resistance to displacement of the fibers or filaments upon impact of a projectile, i.e., a bullet or shrapnel, typically multiple layers of such fabrics must be used to construct the ballistic resistant article. Such articles can be heavy as a result. The use of multiple layers of fabric can also compromise the flexibility of the resultant article. These factors can in turn reduce wearer comfort and mobility. Further, the use of a large number of fabric layers can increase the cost of such articles.